gettime: don't attempt to fixup what looks like a backwards clock
It could just be a wrap. The code is buggy, kill it, we'll deal
with the wrap later.
Signed-off-by: Jens Axboe <axboe@fb.com>
diff --git a/gettime.c b/gettime.c
index 6a7e35f..8e53f83 100644
--- a/gettime.c
+++ b/gettime.c
@@ -20,9 +20,8 @@
int tsc_reliable = 0;
struct tv_valid {
- struct timeval last_tv;
uint64_t last_cycles;
- int last_tv_valid;
+ uint64_t last_tv_valid;
};
#ifdef CONFIG_TLS_THREAD
static __thread struct tv_valid static_tv_valid;
@@ -136,7 +135,7 @@
}
#endif
-static void *__fio_gettime(struct timeval *tp)
+static void __fio_gettime(struct timeval *tp)
{
struct tv_valid *tv;
@@ -171,12 +170,11 @@
uint64_t usecs, t;
t = get_cpu_clock();
- if (tv && t < tv->last_cycles) {
- dprint(FD_TIME, "CPU clock going back in time\n");
- t = tv->last_cycles;
- } else if (tv)
- tv->last_cycles = t;
+ if (t < tv->last_cycles && tv->last_tv_valid)
+ log_err("fio: CPU clock going back in time\n");
+ tv->last_cycles = t;
+ tv->last_tv_valid = 1;
#ifdef ARCH_CPU_CLOCK_CYCLES_PER_USEC
usecs = t / ARCH_CPU_CLOCK_CYCLES_PER_USEC;
#else
@@ -191,8 +189,6 @@
log_err("fio: invalid clock source %d\n", fio_clock_source);
break;
}
-
- return tv;
}
#ifdef FIO_DEBUG_TIME
@@ -201,8 +197,6 @@
void fio_gettime(struct timeval *tp, void fio_unused *caller)
#endif
{
- struct tv_valid *tv;
-
#ifdef FIO_DEBUG_TIME
if (!caller)
caller = __builtin_return_address(0);
@@ -214,23 +208,7 @@
return;
}
- tv = __fio_gettime(tp);
-
- /*
- * If Linux is using the tsc clock on non-synced processors,
- * sometimes time can appear to drift backwards. Fix that up.
- */
- if (tv) {
- if (tv->last_tv_valid) {
- if (tp->tv_sec < tv->last_tv.tv_sec)
- tp->tv_sec = tv->last_tv.tv_sec;
- else if (tv->last_tv.tv_sec == tp->tv_sec &&
- tp->tv_usec < tv->last_tv.tv_usec)
- tp->tv_usec = tv->last_tv.tv_usec;
- }
- tv->last_tv_valid = 1;
- memcpy(&tv->last_tv, tp, sizeof(*tp));
- }
+ __fio_gettime(tp);
}
#if defined(ARCH_HAVE_CPU_CLOCK) && !defined(ARCH_CPU_CLOCK_CYCLES_PER_USEC)
@@ -336,8 +314,10 @@
struct tv_valid *t;
t = calloc(1, sizeof(*t));
- if (pthread_setspecific(tv_tls_key, t))
+ if (pthread_setspecific(tv_tls_key, t)) {
log_err("fio: can't set TLS key\n");
+ assert(0);
+ }
}
static void kill_tv_tls_key(void *data)